1.4 kwh/mi on interstate…disappointed.

[chl]

You are pushing a huge brick through the air, and you are essentially at sea level. The loss in inefficiency would be the same for an ICE F150. There are many, many threads discussing this issue.

Yes aerodynamics kicks in as the killer with speed - so ICE estimates:
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Fuel efficiency typically decreases as a vehicle's speed increases, and the amount of fuel lost per mile per hour varies by vehicle and driving speed:

40–50 mph: The optimal cruising speed for most vehicles
50–60 mph: Fuel economy decreases by an average of 12.4%
60–70 mph: Fuel economy decreases by an average of 14%
70–80 mph: Fuel economy decreases by an average of 15.4%
55 mph: Midsize conventional gasoline cars achieve their best fuel economy at this speed
Over 55 mph: Drivers typically lose 1–2% of their fuel efficiency for each mile per hour they drive over this speed
85 mph: Driving at this speed uses 40% more fuel than at 70 mph

Other factors that can impact fuel efficiency include:
Aggressive acceleration: Can directly lower fuel efficiency
Harsh braking: Can directly lower fuel efficiency
Excessive idling: Can directly lower fuel efficiency
Vehicle age: As a vehicle ages, it can lose efficiency due to wear and tear and fuel injector deposits
-----
FOR EV's:

Electric vehicles (EVs) become less efficient at higher speeds:

Drag: The force a vehicle encounters when moving through air increases with the square of the vehicle's speed. This means that doubling the speed of an EV quadruples the drag force.

Energy consumption: The faster an EV goes, the more energy it consumes. For example, one driver found that their Chevrolet Bolt EV's efficiency dropped from 6 miles/kWh to 4 miles/kWh when they drove faster.

Range: Driving at higher speeds can result in a significant loss of range. For example, one driver reported that their 2017 Chevy Volt only had a range of about 44 miles at 75 miles per hour, compared to its rated range of 53 miles per charge.

Other factors that can affect an EV's efficiency include:

Wind: Headwinds increase resistance, which means the motor has to work harder.
Payload: The more passengers and cargo in the vehicle, the less efficient it will be.
Tire traction: Poor tire traction can result in less efficiency.
Temperature: The temperature can affect how much energy an EV uses. For example, in January 2021, the Tesla Model 3 used 358 watt-hours to cover each mile, but in August 2020, it used 256 watt-hours per mile.

To increase an EV's battery range, it's best to drive more slowly, especially when possible.
-----

The above were presented to me by Generative AI...but they seem pretty accurate.

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[NCevGuyF150]

Had my lightning for just about 10 days and while I love it so far, I was pretty disappointed with this efficiency. Of those 49 miles, 36 or so were on the interstate, setting cruise to 79 mph. All flat on I-95 in Coastal Georgia. The first 13 or so miles were from my house to interstate, and up to that point it had gotten about 2 to 2.1 on those 13 miles (cityish driving). Outside temp hovered between 65-70 as sun was coming up.

Is this what I should expect for interstate driving at that speed? It was close to 30% of the battery. Will it take a while to “break in”? I’ve got about 750 miles on the truck. At this point I might just as well put 37” mud tires on it

Good morning, just reading your post. That is rather disappointing however, I drove my 22 F150 lightning extended range to Miami and back to Charlotte, approximately 1800 miles. I averaged about 2.1. But I drove between 65 and 70 mph the whole trip. You may want to have the Ford dealer check your truck. That seems a little bit low however there is a significant amount of air at 80 mph.

 

[Kit2874]

setting cruise to 79 mph.

That's like saying I was disappointed with my gas f150 it's mpg is 25 and only getting 17...speed kills both kwh/ MPG just saying..

 

[ScubaSteve_TheReal]

I think you'll be surprised by how much tire pressure plays a role in your efficiency. I believe most of the factory tires call for 36psi. I typically run mine closer to 40.

I run mine at 42psi based on cold tires. That’s the sweet spot I’ve found personally. It’s also the recommended pressure for my truck.

 

[RickLightning]

"The Factory calls for" depends on your wheel/tire configuration. Some are 36 pounds. Mine are 42 pounds.

When I picked up the truck in Missouri to drive it home, I told them that FordPass showed the tires at 35PSI, so they needed to increase them to 42. They stared at me, and the sales manager said "we always do the new car checklist and it tells them to check the doorjamb". We went out to the truck, opened the door, and saw the 42 pounds. He then took out his tire gauge (nevermind that FordPass showed 35psi) and said "I'll be damned" and drove the car over and filled all 4 tires himself.

 

[Lomilar]

Dogpiling, but here we go.

I made a little spreadsheet model of rolling and air resistance using the F150 Lightning's parameters, and this graph hopefully helps:

Ignoring the absolute precision of the numbers, what it's saying, like others, is that you can get double the range going 25mph as going 60mph. At speed, around 55 to 85 mph, each 5 mph gives or takes 10% +- 1% of your range. There are lots of variables that can affect this, though. Here are some of them:

So, if you have 200 miles of range left (calculated based on wh/mile at current speed, not on the GOM) and need to go 220 miles, go 5mph slower.

 

[Mikonopolis]

Altitude, temperature, climate - all big impacts. But the biggest one for me on the highway is speed. On the same route, same condition - going 65 to 70 in the right lane with the big rigs drove my Mi/KWH about 25% higher.

Had my lightning for just about 10 days and while I love it so far, I was pretty disappointed with this efficiency. Of those 49 miles, 36 or so were on the interstate, setting cruise to 79 mph. All flat on I-95 in Coastal Georgia. The first 13 or so miles were from my house to interstate, and up to that point it had gotten about 2 to 2.1 on those 13 miles (cityish driving). Outside temp hovered between 65-70 as sun was coming up.

 

[Mikonopolis]

There is so much to love in this reply. But the best part has to be Freedom Unit. Thank you. -GW

Dogpiling, but here we go.

I made a little spreadsheet model of rolling and air resistance using the F150 Lightning's parameters, and this graph hopefully helps:
View attachment 90316
Ignoring the absolute precision of the numbers, what it's saying, like others, is that you can get double the range going 25mph as going 60mph. At speed, around 55 to 85 mph, each 5 mph gives or takes 10% +- 1% of your range. There are lots of variables that can affect this, though. Here are some of them:
View attachment 90319
So, if you have 200 miles of range left (calculated based on wh/mile at current speed, not on the GOM) and need to go 220 miles, go 5mph slower.

 

[NCevGuyF150]

"The Factory calls for" depends on your wheel/tire configuration. Some are 36 pounds. Mine are 42 pounds.

When I picked up the truck in Missouri to drive it home, I told them that FordPass showed the tires at 35PSI, so they needed to increase them to 42. They stared at me, and the sales manager said "we always do the new car checklist and it tells them to check the doorjamb". We went out to the truck, opened the door, and saw the 42 pounds. He then took out his tire gauge (nevermind that FordPass showed 35psi) and said "I'll be damned" and drove the car over and filled all 4 tires himself.

I have found that if I do not run the maximum amount of tire pressure stated on the sidewall of the tires. I end up with rounded edges on my tires. And I do find that I get a lot better efficiency with the truck

 

[RickLightning]

I have found that if I do not run the maximum amount of tire pressure stated on the sidewall of the tires. I end up with rounded edges on my tires. And I do find that I get a lot better efficiency with the truck

Sure, less rolling resistance. You'll also get a much firmer ride, worse stopping power, cornering ability, etc. with less rubber on the road. It's a tradeoff.

 

[Ishkatan]

The lates software update has also been playing havoc with mi/kWh estimates. I've gotten "This Trip" numbers as low as 1.4 for the first couple miles then up to 2.0 for a 15 mile trip... then I'll get 4.1 on the next trip. The "Trip 1" counter shows me averaging 2.3 over longer distances that include driving at 40-50 mph as well as some 70 mph highway stretches. These are summer numbers. I also saw my range drop to 2.0 for a 300 mile trip - 4 Americans (fat) and bed full of furniture with headboard legs sticking up a foot+ over the cab roof on I-95. A traffic jam helped improve the range - slower means more MPGe.
My bottom line - check my % level and charge with plenty of range left. Going from 80-90 to 30% is a couple hours of highway driving at least and by then I need a break anyway. An hour of fast charging gets me into the 9x% range and several pounds fatter.

 

[Ventorum94]

Don’t forget, it’s more time efficient to drive faster and charge more often. The lower efficiency doesn’t mean you’re getting anywhere slower. It only means it costs more to get there. People have a mental block around stopping but compared to driving 60mph and charging 20% less, you don’t make up the extra time gained by driving 80mph.

“it’s more time efficient to drive faster and charge more often.”
It depends, doesn’t it? Have you ever spent 15min getting through backed-up traffic into a Buc-ee’s to charge? And then 20min to get out of Buc-ee’s and back onto the highway? Maybe not every charging stop wastes as much time not-charging, but consider the illustration. If driving 80-85mph means 1.6mi/kWh, and driving 70mph means 2.1mi/kWh, you‘re going to need about 30% more kWh- and all that extra charging means not just time spent plugged in, but all that time spent getting off the highway and to the chargers.

 

[Firn]

“it’s more time efficient to drive faster and charge more often.”
It depends, doesn’t it? Have you ever spent 15min getting through backed-up traffic into a Buc-ee’s to charge? And then 20min to get out of Buc-ee’s and back onto the highway? Maybe not every charging stop wastes as much time not-charging, but consider the illustration. If driving 80-85mph means 1.6mi/kWh, and driving 70mph means 2.1mi/kWh, you‘re going to need about 30% more kWh- and all that extra charging means not just time spent plugged in, but all that time spent getting off the highway and to the chargers.

Use A Better Route Planner to do the math for you. You can set speed over the speed limit and you can set charger overhead time.

Ultimately even over the 1000 mile trip I used going faster was faster, that included increasing overhead time for every stop. In the end it didn't add a large number more stops which is why it is more efficient.

For fun I just ran it again.

From my house to el Paso TX, ~1600 miles, and setting overhead to 15 minutes per stop.

At the speed limit, 32 hours, at 130% of the speed limit, 31 hours.

It added 3 stops, charge time went up by 3 hours but drive time went down by 4.

 

[Ventorum94]

Use A Better Route Planner to do the math for you. You can set speed over the speed limit and you can set charger overhead time.

Ultimately even over the 1000 mile trip I used going faster was faster, that included increasing overhead time for every stop. In the end it didn't add a large number more stops which is why it is more efficient.

For fun I just ran it again.

From my house to el Paso TX, ~1600 miles, and setting overhead to 15 minutes per stop.

At the speed limit, 32 hours, at 130% of the speed limit, 31 hours.

It added 3 stops, charge time went up by 3 hours but drive time went down by 4.

So, driving 85mph instead of 65mph saves a whopping one hour on a 1600mi drive? With an additional three charging stops? What if on one or more of those charging stops, the overhead time ends up being a lot longer due to having to wait in line to charge? And only 15min overhead time assumption? What about the long lines of cars waiting for Buc-ee’s, for example- no way to get in and out of their parking lot in 15min. Adding more charging stops to a trip compounds the risk of a charging queue, or having to use a low power or de-rated charger, or the frustration of a longer-than-anticipated overhead time. And what is the risk of “traffic stop overhead time“ from driving 20mph over the speed limit, for 1600mi (to say nothing of the potential expense in fines and insurance premiums)?

 

[RickLightning]

This ^^^

ABRP lets you tweak settings and play, stops can be set to Few but long on the left, quickest arrival in the middle, and short but many on the right.

What all these apps fail to take into account are the following (at least):

- Time it takes to get from the highway to the charging spot. I've had 1/2 dozen traffic lights, all red.
- Time it takes to get a session going at a working charger.
- Charger speed adversely impacted by a) other vehicles, b) temperature, or c) fault location (like the whole location, all chargers, rebooting at the same time).

I use the middle option (quickest arrival). I drive 73 or so most of the time, and will charge to 80% if the recommendation is to charge anywhere between 65 and 80, because you might as well.

As I drive on the trip, I note if my efficiency is beating the recommendation, and if so I adjust it. The Lightning battery pack holds heat much better than the Mach-E, and the default settings in ABRP don't reflect that.

The other thing for us is driving an efficient trip. That means leaving at 8AM with 100% and preconditioned (winter), and charging 3 to 4 times, ending the trip around dinner time (hopefully near a brewery), and getting free hotel charging overnight to 100%. Sometimes you can't find a hotel with charging. Sometimes it isn't free, and sometimes it's so slow you have to DC fast charge to a certain point, and then move to the hotel charger. I do the research, and calculate what SOC I need to start with at the hotel to be 100% in the morning.

It's all about planning.

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